Singaporeans voted Friday in a general election that could further chip away at the five decade-long dominance of the country's long-ruling People's Action Party.

The PAP is seen as nearly certain to retain a wide majority in parliament, but faces a strong challenge from opposition parties, which for the first time are contesting all 89 seats.

The party was co-founded by Singapore's independence leader Lee Kuan Yew, who died earlier this year. It is now led by his son, Prime Minister Lee Hsien Loong.

Although the PAP currently has 80 seats in parliament, it secured just 60 percent of the popular vote in the last elections in 2011 - its worst ever performance.

The government faces public frustration over a high immigration rate that has held down wages and pushed up housing prices, even as the nation enjoyed spectacular economic growth.

However, the ruling party remains popular for policies that have transformed the city-state from a poor, colonial port into a rich, regional hub for business.

The government continues to dominate the country's major media outlets and there is only limited room for dissent. The rise of social media and independent media outlets, however, has allowed for a wider degree of free speech.

Singapore has about two and a half million eligible voters. The polls close at 8:00 p.m. local time. First results are expected hours later.